Binder composition for electrical storage device electrodes, slurry for electrical storage device electrodes, electrical storage device electrode, and electrical storage device

Abstract

An electrical storage device electrode binder composition containing a polymer (A) and a liquid medium (B). A repeating unit (A4) derived from an unsaturated carboxylic acid compound is included in the polymer (A) in an amount of 5-40 parts by mass based on 100 parts by mass of the total repeating units in polymer (A). The polymer (A) is in particle form, and the polymer particles have a surface acid content of 1-6 mmol/g.

The invention claimed is: 
     
       1. An electrical storage device electrode binder composition comprising:
 a polymer (A) and a liquid medium (B), 
 wherein the polymer (A) comprises:
 a repeating unit (A1) comprising, in reacted form, a conjugated diene compound in an amount of 30 to 50 parts by mass, 
 a repeating unit (A2) comprising, in reacted form, an aromatic vinyl compound in an amount of 10 to 50 parts by mass, 
 a repeating unit (A3) comprising, in reacted form, a (meth)acrylate compound in an amount of 1 to 10 parts by mass, 
 a repeating unit (A4) comprising, in reacted form, an unsaturated carboxylic acid in an amount of 5 to 40 parts by mass, and 
 a repeating unit (A5) comprising, in reacted form, an alpha, beta-unsaturated nitrile compound in an amount of 1 to 10 parts by mass, 
 
 
       based on 100 parts by mass of total repeating units included in the polymer (A), and
 wherein the polymer (A) is in particle form, and the polymer particles have a surface acid content of more than 1 mmol/g and 6 mmol/g or less. 
 
     
     
       2. The electrical storage device electrode binder composition according to  claim 1 , wherein the polymer particles have a zeta potential of −80 to −10 mV. 
     
     
       3. The electrical storage device electrode binder composition according to  claim 1 , wherein a mass ratio W A4 /W A1  is 0.3 to 1, and a mass ratio W A4 /W A5  is 1.8 to 25, wherein W A1  is a mass of the repeating unit (A1), W A4  is a mass of the repeating unit (A4), and W A5  is a mass of the repeating unit (A5). 
     
     
       4. The electrical storage device electrode binder composition according to  claim 1 , wherein a mass ratio W A2 /W A1  is 0.3 to 1.5, wherein W A1  is a mass of the repeating unit (A1), and W A2  is a mass of the repeating unit (A2). 
     
     
       5. The electrical storage device electrode binder composition according to  claim 1 , wherein the polymer (A) comprises two or more repeating units comprising, in reacted form, an unsaturated carboxylic acid as the repeating unit (A4). 
     
     
       6. The electrical storage device electrode binder composition according to  claim 1 , wherein the polymer particles have an average particle size of 50 to 400 nm. 
     
     
       7. The electrical storage device electrode binder composition according to  claim 1 , further comprising an isothiazoline-based compound (C). 
     
     
       8. The electrical storage device electrode binder composition according to  claim 7 , comprising the isothiazoline-based compound (C) at a concentration of 50 ppm or more and less than 200 ppm. 
     
     
       9. An electrical storage device electrode slurry comprising the electrical storage device electrode binder composition according to  claim 1 , and an active material. 
     
     
       10. The electrical storage device electrode slurry according to  claim 9 , comprising a silicon material as the active material. 
     
     
       11. The electrical storage device electrode slurry according to  claim 9 , having a thread-forming capability of 30 to 80%. 
     
     
       12. An electrical storage device electrode comprising a collector, and an active material layer that is formed by applying the electrical storage device electrode slurry according to  claim 9  to a surface of the collector, and drying the applied electrical storage device electrode slurry. 
     
     
       13. The electrical storage device electrode according to  claim 12 , comprising silicon in an amount of 2 to 30 parts by mass based on 100 parts by mass of the active material layer. 
     
     
       14. The electrical storage device electrode according to  claim 12 , wherein the active material layer has a polymer distribution coefficient of 0.6 to 1.0. 
     
     
       15. An electrical storage device comprising the electrical storage device electrode according to  claim 12 . 
     
     
       16. The electrical storage device electrode according to  claim 12 , wherein the active material layer comprises a silicon material.